Deep and disseminated dermatophytosis in immunocompromised populations — A systematic review

Background: Dermatophytes—a group of obligate keratinophilic fungi that infect the skin, hair and nails—represent the most common cause of fungal infections worldwide. In immunocompromised individuals, a growing body of literature has documented rare instances of dermatophyte infections of the dermis and subcutaneous tissue, which can lead to deep dermatophytosis with systemic dissemination and pseudomycetoma as secondary complications. Objectives: To assess patient characteristics, risk factors, diagnostic evidence and treatment options for deep dermatophytosis. Methods: A systematic review was conducted in June 2025 to identify patients presenting with deep dermatophytosis of the glabrous skin; all cases were validated by confirmatory testing per histopathologic examination and fungal culture. Majocchi's granuloma diagnoses were excluded. Results: The search yielded 96 studies (1954–2025) documenting 134 patients. The number of reports has notably increased since the 21st century; however, diagnosis remains challenging due to possible dermatophyte adaptation in the dermal/subcutaneous environment. Trichophyton rubrum is the most frequently isolated pathogen. Acquired immunodeficiencies (e.g. renal transplant recipients) and primary immunodeficiencies (e.g. CARD9, STAT3 mutations) elevate the risk of deep dermatophytosis. Systemic dissemination, often accompanied by lymphadenopathy, was reported in 24 patients, with the most common being infection of the axillary and inguinal lymph nodes. Infections of the bones, lungs, and brain were also reported. Terbinafine (125–1000 mg/day) and itraconazole (100–400 mg/day), with adjunctive topical antifungals and surgical interventions, have been tried for deep dermatophytosis. The use of newer triazoles (voriconazole, posaconazole) should follow the principles of antifungal stewardship and therapeutic drug monitoring recommendations. Multidrug resistance is a potential concern in immunocompromised patients who will often require extended or lifelong treatment. Conclusions: Healthcare providers should be cognizant that dermatophytosis may become invasive and disseminated in immunocompromised populations. Testing and early treatment should not be overlooked in these patients.